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Monk G

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If 20 g of ethanol (formula mass 46) and 30 g of water (formula mass 18) are mixed together, the mole fraction of ethanol in this mixture is.
A. 0.261
B. 0.207
C. 0.739
D. 0.793
 
Solution
To find the mole fraction of ethanol in the mixture, you need to calculate the moles of ethanol and water first.

  1. Moles of Ethanol (C2H5OH):
    • Given mass of ethanol = 20 g
    • Formula mass of ethanol (C2H5OH) = 46 g/mol
    • Moles of ethanol = (Given mass of ethanol) / (Formula mass of ethanol) = 20 g / 46 g/mol = 0.4348 moles
  2. Moles of Water (H2O):
    • Given mass of water = 30 g
    • Formula mass of water (H2O) = 18 g/mol
    • Moles of water = (Given mass of water) / (Formula mass of water) = 30 g / 18 g/mol = 1.6667 moles
Now, calculate the mole fraction of ethanol:

Mole fraction of ethanol (X_ethanol) = (Moles of ethanol) / (Total moles in the mixture) = (0.4348 moles) / (0.4348 moles + 1.6667 moles) = 0.4348 /...
To find the mole fraction of ethanol in the mixture, you need to calculate the moles of ethanol and water first.

  1. Moles of Ethanol (C2H5OH):
    • Given mass of ethanol = 20 g
    • Formula mass of ethanol (C2H5OH) = 46 g/mol
    • Moles of ethanol = (Given mass of ethanol) / (Formula mass of ethanol) = 20 g / 46 g/mol = 0.4348 moles
  2. Moles of Water (H2O):
    • Given mass of water = 30 g
    • Formula mass of water (H2O) = 18 g/mol
    • Moles of water = (Given mass of water) / (Formula mass of water) = 30 g / 18 g/mol = 1.6667 moles
Now, calculate the mole fraction of ethanol:

Mole fraction of ethanol (X_ethanol) = (Moles of ethanol) / (Total moles in the mixture) = (0.4348 moles) / (0.4348 moles + 1.6667 moles) = 0.4348 / 2.1015

Now, calculate this fraction:

X_ethanol ≈ 0.207

So, the mole fraction of ethanol in the mixture is approximately 0.207.

The correct answer is B. 0.207.
 
Solution
To find the mole fraction of ethanol in the mixture, we first need to calculate the number of moles of ethanol and water.

Number of moles of ethanol = mass of ethanol / molar mass of ethanol
Number of moles of ethanol = 20 g / 46 g/mol
Number of moles of ethanol = 0.435 moles

Number of moles of water = mass of water / molar mass of water
Number of moles of water = 30 g / 18 g/mol
Number of moles of water = 1.667 moles

Next, we need to calculate the total number of moles in the mixture.

Total number of moles = moles of ethanol + moles of water
Total number of moles = 0.435 + 1.667
Total number of moles = 2.102 moles

Finally, we can calculate the mole fraction of ethanol.

Mole fraction of ethanol = moles of ethanol / total moles
Mole fraction of ethanol = 0.435 moles / 2.102 moles
Mole fraction of ethanol = 0.207

Therefore, the mole fraction of ethanol in the mixture is approximately 0.207. Therefore, the correct answer is B. 0.207.
 

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